tests: explicitly define compression engines for tests
The zstd compression engine requires C extensions and isn't present
in pure Python builds.
The compression engine list leaks into the server capabilities string.
Unless we're testing functionality specific to a compression format,
the set of compression formats supported by a server doesn't matter
much.
So this commit explicitly defines the server's compression engines for
some tests so behavior is consistent between pure and non-pure builds.
Differential Revision: https://phab.mercurial-scm.org/D3431
== Local
Ready.
Un and Deux
Eins und Zwei
One and Two
Eins und Zwei
Uno und Due
== Remote
Ready.
REQ: foo?one=Vo&two=Efvy
-> Vo!boe!Efvy
Un and Deux
REQ: bar?b=Fjot&a=[xfj
-> Fjot!voe![xfj
Eins und Zwei
REQ: batch?cmds=foo:one=Pof,two=Uxp;bar:b=Fjot,a=[xfj;bar:b=Vop,a=Evf
-> Pof!boe!Uxp;Fjot!voe![xfj;Vop!voe!Evf
One and Two
Eins und Zwei
Uno und Due